I have an intel MB DG41CN with 2 GB (two modules of 1 GB) DDR2 667 MHz memory. I consulted the manual to check the maximum memory quantity of the MB and I found it is 8 GB, probably 2 modules of 4 GB, as the MB has two slot. So I bought a 4 GB Markvision memory module of 800 MHz to do an upgrade. When I installed the module and tuned the computer on I got no image on the display and 3 beeps as if there was no memory there. Then I tried to upgrade the bios to the most recent version (2001), because my version was from 2009, but it didn't solve my problem. Now I as: does this MB really support 8 GB (2 x 4 GB) or is it some kind of incompatibility? It's strange because the two modules of 1 GB I'm using right now are also from Markvision. Please help me!

If you have a look at the System Memory support page for your specific board it explains some of the requirements for memory to work with this board. One requirement is that the memory must NOT be ECC memory. You also wrote that you'd bought a (singular) 4 GB module for an upgrade rather than a pair - how did you test this - ie what modules(s) plugged into what slot? Even though boards such as this should be able to work with one slot unoccupied, in my experience, attempting to do so is often problematic. There may also be issues related to ram 'density' so talk to your supplier about such options.

Normally if you go to most memory manuyfacturers websites, they have a search function which will match the correct modules for a given motherboard but I can't find such a website for Markvision brand ram - maybe a call to your memory supplier would get the information of precisely what RAM modules you need. What OS are you using with the board BTW (have you checked it'll fully utilise that amount of RAM)? http://msdn.microsoft.com/en-us/library/windows/desktop/aa366778(v=vs.85).aspx

I was using windows 7 32 bits, but I decided to upgrade the ram because I would install the 64 bits version, which by the way I've already done. But considering you question about the OS I thought the module should work independently of the OS. In the case the OS would recongnize less than 4 GB, right? This moldule was not ECC, and I tested it in both slot (A and B), but it did not work. It strange because I tested one of my 1GB modules alone and it worked, but I think you are right about using a pair of memories. Earlier today I went to the store I changed my 4 GB module for two 2GB modules and it worked, so I it was probabily an incompatibility with the controller chip of the memory or an issue related to ram density, as you said.

As I solved the problem the topic can be now closed. Anyway, thank you very well for your help. Next time I will certainly buy some Kingston modules.

But considering you question about the OS I thought the module should work independently of the OS. In the case the OS would recongnize less than 4 GB, right?

The module should work independantly of the OS and in the case of x86 versions of Win 7 you should have had 3.2 GB or so of memory showing as usable in Windows (the rest is still in use, just behind the scenes with system hardware such as built in graphics). Had you installed 8 GB on an OS that didn't support that much, I believe it would just see it's limit amount but would still run (not sure if there'd be reliability concerns because I've never tried that).

My DG45ID Win 7 x86 PC shows 4.00 GB installed and 3.18 GB usable. I use 2 x 2 GB modules with this board and I've never run low on memory with this PC. I have tried it with x64 Win 7 (which seemed to run slower on this system, also having reduced compatibility with my peripheral hardware). I've not tried this board with just one module but as I say, I have encountered problems with just one high density module on other, different, boards in the past and have seen similar problems reported here many times in the past. Aside from possible reliability issues, you get faster performance if you have a matching pair because you then utilise 'dual channel' mode so the choice is easy. 8 GB on older boards is really only justified if you have lots of very demanding apps open at the same time or the computer is performing server functions IMO. I think you're probably better off saving your money towards your next PC and sticking with the 4 GB you now have. Glad I could be of some assistance